Science & Technology
New Drug for Amoebiasis
- 15 Jun 2020
- 4 min read
Why in News
Recently, researchers from the Jawaharlal Nehru University (JNU) have developed new drug molecules against the protozoa ‘Entamoeba histolytica’ that causes amoebiasis.
Key Points
- The Protozoa and High Oxygen Level:
- The protozoa is anaerobic or microaerophilic in nature such that it cannot survive high concentrations of oxygen.
- Anaerobic organisms are those who exist in the absence of free oxygen.
- A microaerophilic atmosphere is ideal for a microorganism that can grow under reduced oxygen and increased carbon dioxide levels.
- However, during infection, it faces a high surge of oxygen inside the human body. The organism synthesizes large amounts of cysteine to counter oxidative stress.
- The protozoa is anaerobic or microaerophilic in nature such that it cannot survive high concentrations of oxygen.
- Synthesis of Cysteine:
- This pathogen deploys cysteine as one of the essential molecules in its defence mechanism against high oxygen levels. It expresses two crucial enzymes for synthesizing cysteine.
- Cysteines are enzymes that degrade proteins in the body.
- Cysteine biosynthesis is crucial for the survival of E. histolytica and for similar protozoan parasites.
- This pathogen deploys cysteine as one of the essential molecules in its defence mechanism against high oxygen levels. It expresses two crucial enzymes for synthesizing cysteine.
- JNU Research:
- Researchers have characterized and determined the molecular structures of both the crucial enzymes.
- They have also successfully screened for potent inhibitors for one of the enzymes, O-acetyl L-serine sulfhydrylase (OASS).
- Some of these inhibitors can check the growth of this organism with high efficacy by targeting their pathways.
- The identified molecules can lead to the development of drug molecules.
Protozoa
- Protozoans are the single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris.
- Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes, which have no membrane-bound organelles.
- A parasite is an organism that lives on or in a host and gets its food from or at the expense of its host. E.g. plasmodium parasite which causes malaria.
- Habitat: Mostly they are aerobic (with oxygen) but some are anaerobic (without oxygen) and present in the rumen or human intestine.
- Size and Shape: The size and shape of Protozoa vary greatly, from microbial (1µm) to large enough and can be seen by the naked eye.
- Nutrition: Protozoans are heterotrophs and have holozoic nutrition.
- Holozoic nutrition can be defined as a method of nutrition which involves the ingestion of some complex organic substances (such as parts of a plant or animal) that may be in the solid or the liquid form.
Entamoeba histolytica
- According to the World Health Organization (WHO), Entamoeba histolytica is the third-leading cause of morbidity and mortality due to parasitic disease in humans.
- Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 35-50 million people worldwide.
- A parasitic disease is an infectious disease caused or transmitted by a parasite. E.g. Malaria.
- It causes amoebiasis or amoebic dysentery, which is highly prevalent in developing countries.
Amoebiasis
- It is a disease caused by the parasite Entamoeba histolytica.
- Amoebiasis infection is most common in tropical areas with untreated water. E.g. India.
- It spreads through drinking or eating uncooked food, such as fruit, that may have been washed in contaminated local water.
- If symptoms occur, they may be mild and include cramping and diarrhoea.
- It can be treated through antibiotics.